diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index c3f1463..895bf0e 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "1.2.0"
+  ".": "2.0.0"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ca05658..3fdc404 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,20 @@
 # Changelog
 
+## [2.0.0](https://github.com/gradienthealth/cloud_optimized_dicom/compare/v1.2.0...v2.0.0) (2026-05-07)
+
+
+### ⚠ BREAKING CHANGES
+
+* **PROC-1668:** `cloud_optimized_dicom` now depends on upstream `pydicom>=3.0` instead of the `pydicom3` fork. Downstream impact:
+    - `isinstance` checks against `pydicom3.*` on cod-returned objects will start returning `False` — switch to `pydicom.*`. (This is exactly the bug PROC-1668 fixes for gradient-beam.)
+    - Installing `cloud-optimized-dicom` no longer transitively installs `pydicom3`. Code that imported `pydicom3` only because cod brought it in must either switch to `import pydicom` or add the fork to its own dependencies.
+    - Environments pinned to `pydicom<3` will no longer resolve. Bump to `pydicom>=3.0`.
+
+
+### Features
+
+* **PROC-1668:** drop pydicom3 fork in favor of upstream pydicom ([#134](https://github.com/gradienthealth/cloud_optimized_dicom/pull/134)) ([42d5e7e](https://github.com/gradienthealth/cloud_optimized_dicom/commit/42d5e7eb8110c120a7feb41085a5efc3270ef586))
+
 ## [1.2.0](https://github.com/gradienthealth/cloud_optimized_dicom/compare/v1.1.1...v1.2.0) (2026-04-30)
 
 
diff --git a/pyproject.toml b/pyproject.toml
index a13cd46..d3a552f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "cloud-optimized-dicom"
-version = "1.2.0"
+version = "2.0.0"
 description = "A library for efficiently storing and interacting with DICOM files in the cloud"
 readme = "README.md"
 authors = [